San Onofre studies wait for answers

Plant operator wants utility customers to pay for safety inquiry

Members of the media, wearing protective suits and masks, visit the Unit 3 and Unit 4 reactor buildings of tsunami-crippled Fukushima Dai-ichi nuclear power station of Tokyo Electric Power Co., during a press tour escorted by TEPCO officials, in Okuma, Fukushima prefecture, northeastern Japan, Tuesday, Feb. 28, 2012. Nearly a year after it suffered multiple meltdowns, the tsunami-hit Japanese nuclear plant is in shambles, barely running on a patchwork of makeshift equipment.(AP Photo/Kimimasa Mayama, Pool)— AP

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Members of the media, wearing protective suits and masks, visit the Unit 3 and Unit 4 reactor buildings of tsunami-crippled Fukushima Dai-ichi nuclear power station of Tokyo Electric Power Co., during a press tour escorted by TEPCO officials, in Okuma, Fukushima prefecture, northeastern Japan, Tuesday, Feb. 28, 2012. Nearly a year after it suffered multiple meltdowns, the tsunami-hit Japanese nuclear plant is in shambles, barely running on a patchwork of makeshift equipment.(AP Photo/Kimimasa Mayama, Pool)
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New seismic and tsunami studies remain on hold at the seaside San Onofre nuclear power plant north of San Diego as regulators decide if utility customers should pay for the entire project and whether additional oversight is necessary.

Plant operator Southern California Edison is asking that utility customers, not shareholders, fund a $64 million study that would survey faults near the San Onofre plant using three-dimensional mapping tools also used for oil and gas exploration.

Edison enlarged the scope of its study in reaction to damage at Japan’s Fukushima Daiichi nuclear plant from the magnitude-9 quake off northeastern Japan on March 11, 2011, and the tsunami that followed.

A 2008 California Energy Commission report looking at California’s two nuclear plants found that San Onofre could experience larger and more frequent earthquakes than the maximum magnitude-7 temblor predicted when the plant was designed.

The dual-reactor plant is not necessarily unsafe, because it was built to withstand greater jostling than predicted and is not known to be located on top of a major fault. There are, however, significant faults near the plant, including hidden “blind” thrust faults.

San Onofre’s two reactors are built to withstand a peak ground acceleration of 0.67 times the force of gravity, on a scale used for building codes and design risk.

Plant officials say a 7.0 earthquake on the long-dormant Cristianitos Fault, five miles from the plant, would generate peak ground acceleration of about 0.35 G-forces.

“The $64 million is supposed to buy you peace of mind … and tell you whether that plant is built to withstand the seismic footprint,” said Rochelle Becker, executive director of the Alliance for Nuclear Responsibility.

California’s offshore geology makes it far less prone to tsunamis than Japan. Edison believes San Onofre is adequately protected by a 30-foot tsunami wall, citing state estimates that say the largest conceivable tsunamis would be less than 23 feet high.

The design basis for the Daiichi plant was a 19-foot tsunami, with the plant located 30 feet above sea level, according to the World Nuclear Association, an industry trade group. The tsunami height as it came ashore a year ago was estimated at 46 feet.

On Friday, the Nuclear Regulatory Commission ordered safety changes for U.S. nuclear plants, including requirements they better assess earthquake risks and cope with incidents they were not initially designed to handle, such as prolonged power blackouts or damage to multiple reactors at the same time. Officials at San Onofre could not be reached immediately for comment.

Meanwhile, a host of environmental groups and civic activists plan to hold a rally outside the San Onofre plant this afternoon to mark the anniversary of the Japan tsunami and call attention to safety concerns at the local installation in North County.

Radiation still leaks from the now-closed Fukushima Daiichi nuclear plant, where 100,000 people have been evacuated from a 12-mile no-go zone.

Advocates for Southern California utility customers are urging state regulators to place a cap on the cost of the San Onofre quake study at $64 million, over objections of Edison and San Diego Gas & Electric, which owns a 20 percent stake in the facility.

The investor-owned utilities have argued that expense containment should not be the first priority when it comes to earthquakes and that customers, not shareholders, should bear the costs.

They made their case in proceedings before the California Public Utilities Commission.

“We are waiting for a proposed decision before beginning the research,” Jennifer Manfre, a spokeswoman for Edison, said in an email.

The Alliance for Nuclear Responsibility wants regulators to require an independent peer review panel for the quake study that would involve state agencies such as the California Energy, Seismic Safety and Coastal commissions as well as the California Geological Survey.

A similar review was required for seismic studies commissioned at the Diablo Canyon nuclear plant by Pacific Gas and Electric.

The outcome of the seismic study could influence Edison’s decision on whether to seek renewal of nuclear licenses at San Onofre that expire in 2022.

“California can’t invest in aging nuclear plants unless we know this is a good investment,” said Becker, the nuclear activist.

San Onofre provides about 20 percent of the area’s electricity. Both reactors are currently offline to resolve concerns raised by a generator steam tube leak.